Good point. Many of us would prefer to use our favorite file managers, some of them 3-pane such as Directory Opus and xplorer² (my favorite). Windows' native Windows Explorer leaves out a lot of functionality. Calling ShellExecuteEx Open would give us a much greater choice of file manager.
My only concern is whether developing PB in Java permits this degree of fine tuning, since one would have expected this to have been implemented much earlier in PB were it possible. This should not be taken to imply criticism of the developers, since I notice that some other Windows shell applications such as Direct Folders do not appear to work in PB, maybe because the required hooks into the Windows shell have not or cannot be implemented.